A Micromechanics Analysis of the Mechanical Behavior of the α-Keratin Composite at Low Strains

Abstract

The two-phase microfibril-mairix composite structure of α-keratin materials is generally accepted to be the basis of any attempt to explain the mechanical properties of these hard mammalian keratins. Despite this general acceptance of the composite analogy, little is known of the individual phase mechanical properties, even with respect to the low strain regime (up to 2-3% strain). This series of papers is an attempt to rectify this situation using finite element techniques appropriate to composite micromechanics analysis. To this end this paper presents an outline of the finite element method for elastic displacement analysis together with a definition of the constraint formulation of the basic composite micromechanics problem. This approach is applicable not only to the α-keratin composite but also to other composite materials, and this is verified for examples of boron epoxy and glass epoxy composites. Subsequent papers demonstrate the application of these techniques to α-keratins both in the native state and in a modified state, resulting from a "setting" process, for which the microfibrillar reinforcement can be considered continuous and discontinuous, respectively.